I have heard a little slop in the extrusion gear and never thought much of it. I glanced and didn’t notice anything obvious. While removing the extrusion module, a piece fell out. The small herringbone gear split into two at the middle, basically giving me only half of the gear while the other half was just along for the ride.
Luckily I had previously printed replacement gears and with it all back together, slop is gone and so is that little noise it made.